When creating a Joomla site, it's incredibly easy to go overboard with extensions. The incredible selection of extensions and templates makes it tempting to implement too many and to spread your knowledge too wide.
As a Joomla integrator, I find it's crucial to find a method of implementing sites which makes it easy to set up, maintain and document a large number of sites. Moderation is a virtue, a least when building Joomla sites.
For instance, the use of too many CCKs, text editors or template frameworks will lead to constant headaches. Particularly in the documentation of a site, it's important to reuse information. If you're using too many extensions and different processes for each site, the task of documenting and training will be so much harder.
Moderation is the process of eliminating or lessening extremes. It is used to ensure normality throughout the medium on which it is being conducted.
I encourage you to search for the set of extensions that fulfill most of your needs, and then stick with that. For me, that's become extensions like K2, JCE, sh404SEF, eXtplorer and a few more. And templates from YooTheme and Joomla Bamboo. Of course, certain sites will need special functions, but I'm talking about the major parts of the sites. The ones that need to be documented and explained to clients and users.
I have some sites with FlexiContent as well, but I guess I'll reserve that for the larger projects where documentation will be custom made in detail anyway. Smaller projects need fast and efficient documentation, which makes reusing content even more important. You could even use a product like JooManuals to create documentation easily.
I will explore the subject of best practices with Joomla more in other posts. If you have any opinions on the subject, please don't hesitate to contact me or comment below.